The present invention relates to vehicle suspension systems and, more particularly, to twin I-beam front suspension systems.
Twin I-beam front suspension designs are known generally in the art. These systems have been difficult at times to tune or develop for solid steering feel and precise handling. The twin I-beam front suspension system of the present invention is directed at improving the known prior art systems in a variety of respects.
In the traditional Haltenberger steering design used on other twin I-beam suspension systems, for example, the toe change with vertical wheel travel of the left front wheel is dependent upon the particular instantaneous vertical displacement of the right front wheel. This dependency between the left and right sides of the twin I-beam suspension tends to contribute to vehicle drift and tire wear, and can impose loads on the steering gear assembly.
In addition, the radius arms of traditional twin I-beam suspension systems attach to the vehicle frame in relatively complex manner, requiting the on-line assembly of a number of components to complete the connection. Furthermore, standard or traditional radius arm bushings can wear rapidly and can also produce unwanted stress noises. Moreover, traditional twin I-beam suspension designs do not adequately balance the toe angle changes between the two front tires due to longitudinal forces. This can contribute to vehicle drift, especially during braking.
It is also difficult to easily, quickly and accurately set the front wheel caster angle in traditional twin I-beam suspension systems. To adjust the caster angle on a typical twin I-beam front suspension system, a mechanic must remove the front coil spring assembly and replace a metal slug which fits around the upper ball joint. Not only is this a difficult and time consuming process, but it is also problematic in that the various sizes of slugs available limit the resolution with which the caster angle may be adjusted. Precise caster angle adjustment is thereby extremely difficult, if not impossible, in traditional twin I-beam front suspension systems.
It therefore is an object of the present invention to provide a tuned and more durable vehicle front suspension system that provides a variety of advantages, including steering and vehicle handling improvements, as well as a reduction in part complexity, steering gear loads and average tire wear.